Coupling mechanism



June 14, 1938.

J. COTAL COUPLING MECHANISM Filed March 8. 1937 are respectively connected with the hand-operated switch |'2 and with the automatic switch In this manner, one or the other of the two first-mentioned switches can be connected with a source of current 2|, or all supply of current can be cut ofi.

The operation of the automatic switch I3 will depend upon the speed of the driven shaft 2. 'Ihis latter actuates, for instance, a centrifugal device which consists chiefly of two sleeves provided with discs. The sleeve 22' is secured to the shaft 2 and the sleeve 23 participates in the rotation of the shaft 2 but is movable lengthwise in the direction of the arrow f1 under the action of a spring 24, and in the opposite direction by the sufficient, the handle l2 Vis placed upon the thrust of the heavy masses 25 which, above a certain speed, are subjected to centrifugal forces whose action upon the disc 23 exceeds the action of the spring 2l.

In the said disc 23,is an annular groove 29 in which is engaged a member 21 secured to'the arm I5 of the switch, which thus participates in the longitudinal movements of the disc 23.

The driven shaft 2 is connected with the wheels or other parts to be actuated, by means of a change speed gear and/or a reversing gear. The rear end ofthe shaft 2 carries, for example. a set of teeth 29 forming a sun-wheel, in engagement with planetary pinions 29, which latter are engaged with an internal tooth wheel 30 forming the second sun-wheel andvparticipating in the rotation of the driven shaft 3|.

The shafts 32 of the planetary pinions 29 are mounted on a disc forming a toothed ring which can be engaged by a fork 34 with a stationary toothed ring or a sector 35 or with the ring 39. When the ring 33 is engaged with the stationary ring 35, this will cause a reduction of speed between the shafts 2 and 3|, with a change in the ldirection of drive; on the contrary, when thel rings 33 and 30 are in engagement, there will be a direct drive between the shafts 2 and 3|.

The operation is asfollows, in the case of manual control. By the contact-piece I8 which is supposed to be connected with the source of current 2|, the current enters the hand-switch, whose handle I2 is in the middle position, as shown in the drawing.

During the time required for the clutch coupling, the -electro-magnets 9 and 9 are not excited, and at this time the coupling ldevice twill fulfil its function, which is to start the driven shaft 2 progressively and without shocks, owing to its internal slipping.

When the speed of the shaft 2 has become contact-piece I3; the electro-magnet 9 is thus excited and it attracts thearmature I| to which it is now secured, thus preventing all slipping between the driving shaft i and the driven shaft 2.

If at slow speed or upon stopping the driving shaft 2, it is desired to change the speed or to,

reverse' the motion, the handle l2 is placed upon the contact-piece I4; the circuit of the electromagnet 9 is broken and the electro-magnet 9 is now excited and it thus attracts the armature `I| and impedes or if necessary `stops its rotation, hence reducing or annulling the residual driving torque due to the hydraulic coupling. The shaft '2 is stopped, thus providing for an easy handling of the parts ensuring the change of speed or the reversal of motion.

The `automatic operation is as follows. By

means of the contact-piece I9 which is oonnected with the source of. current 2| by operating the switch 29. the current is s ent into the automatic switch whose arm II is located on the contact-piece I1, in the idle position. The electro-magnet 9 is now excited, and it holds the armature in the braked position.

When the driving shaft reaches a given speed which is rather slow, the hydraulic driving torque thusV acting lupon the shaft 2 will exceed the braking torque of the electro-magnet 9, so that the shaft 2 is now actuated, and the lateral component due to the centrifugal force thus produced upon the masses 2l will exceed the tension of the spring 24, thus moving the disc 23 in the contrary direction to the arrow f1. The arm i5 at once leaves the contact-piece |1, land the electro-magnet 9 is no longer excited. i

During the time necessary for the clutch coupling, the said coupling device acts as above stated for the case of the manual control, and the switch arm comes nearer the contact-piece Il, then coming upon the latter at a given speed.

The electro-magnet 3 is now excited, thus attract ing the armature and the transmission takes place, without slipping, from the driving shaft to th driven shaft 2.

vBy the action of the spring 2l, the disc 23 tends to move in the direction of the arrow f1 and the arm will return tothe contact-piece l1 when the rotation of the driven shaft 2 greatly decreases or stops; the electro-magnet 9, when thus excited, will brake the armature thus reducing or annulling the residual driving torque, Y and hence providing fora change of speed or a reversal of motion.

In some cases, it may be preferable to use the automatic control only to excite the electromagnet 3. By an arrangement of circuits, the

manual control can be employed to excite the electro-magnet 9 at vthe proper time.

Instead of using the differential device adapted for reverse motion vand for change of speed, as above described, the shaft 2 may be connected ,with the shaft 3| by a reversing gear, for in` stance of the type represented in Fig, 2. The said gear comprises a bevel gear wheel 35, keyed to the shaft 2 and engaging vtwo bevel gear wheels 39 and 31 which are'loose upon the driven shaft 3|, with which they can be connected separately by means of a claw sleeve 39 which is slidable on a key on the shaft 3|.

In order to obtain an increase of the capacity of transmission. a more gradual coupling action,

and a better condition of the surfaces, it may be yof advantage to give a particular forninand hardness to the magnetic friction surfaces.

Figs. 3, 4 and 5 show the armature Il, whose contact faces Ila and IIb are tapered towards the interior, i.,e., the radial section vof the armature is trapezoidal to a very slightdegr'ee, the

large base being located upon the cylindrical part of large diameter.

'I'his arrangement has the advantage of displacing to the exterior the centre of the pressures due to the magnetic attraction, thus increasing the mean radius of the .driving and hence of. obtaining a greater driving capacity.

By the enect of the magnetic attraction, the armature ||iwill at rst b`e applied, by its large diameter, upon the corresponding electro-magnet V9 or 9 with which it makes friction contact (Fig. 4) As the operation takes place in oil, the lubricant which is contained in the annular space of triangular section thus afIorded,vwi1l escape towards the part of large diameter, and will lubricate the portions of the surfaces which have already come into action. This lubrication will last until the deformation produced by the magnetic attraction, when this latter arrives at its maximum degree, permits the Whole of the surfaces to make contact and to effect the driving action without any slipping between these surfaces. (Fig.5.) Y

By hardening the friction surfaces either by a treatment or by the addition of another metal which is harder and adheres perfectly, the friction surfaces can be given an almost'unlimited duration.

Obviously, the invention is not limited to the embodiments herein described and represented, which are given solely by way of example.

Having now described my invention what I v claim as new and desire to secure by Letters Patent is:

l. in combination a driving shaft, a driven shaft, a coupling device between said driving shaft and said driven shaft adapted to allow slipping of one of saidshafts with respect to the other shaft, a stationary member, cooperating electromagnetic braking means carried by said driven shaft and said stationary member adapted to maintain said driven Ashaft in a hired position, and electromagnetic clutching means be ltween. said driving shaft and said driven shaft other shaft, an armature rigidly connected with l said driven shaft, on one side of said ature a` stationary electromagnet adapted to attract said armature and to maintain the same stationary, on the other side of said armature a movable electromagnet rigidly connected with said driving shaft and adapted to attract said armature and to rotate the saine at the speed of said driving shaft, and-means adapted to energize selectively said electromagnet.

3. In a combination according to claim 2, the further feature consisting in that the opposite faces of said armature cooperating with said electromagnets are slightly dii/erging towards the outer periphery of said armature.

4. In combination a 'driving shaft, a driven shaft, an armature rigidly connec with said driven shaft and provided on its opposite sides with faces slightly divergingtowards the outer periphery of said amature, a stationary electro magnet adapted to cooperate with one of said faces of said armature and to maintain said armature stationary, a movable electromagnet rigidly connected with said driving shaft and adapted to cooperate withthe other face of said armature and to rotate said armature at the speed of said driving shaft, and means adapted to energize selectively said electromagnets.

5. In a combination according to claim 4, the further feature consisting in that said faces of said armatures are hardened metal surfaces.

6. A combination according to claim 1, further comprising a source of electric current, a twoway switch having three terminals, one of which being adapted to be connected with said source oi current, two connecting means connected on one hand respectively with said electromagnetic braking means and with said electromagnetic clutching means and on the other hand respectivelyv with the two other terminals of said switch, and means responsive to the speed of said driven shaft and adapted to control said switch and to connect said source of current with said braking means at low speeds of said driven shaft and to connect said source of current with said clutching means at high speeds of said driven shaft.

'7. A combination according to claim 1 further comprising a source of electric current, a rst hand operated two-way switch having three ter- `minals, one of which being connected with said source of current, a secondhand operated twoway switch and a third automatic two-way switch each having three terminals, a rst terminal of each of said second and third switches being connected respectively with the two other terminals of said first switch, connecting means on one hand between said electromagnetic braking 'means and a second terminal of each of said second and third switches and on the other hand between said electromagnetic clutching means and the third terminal of each of said second and third switches, and means responsive to the speed of said driven shaft and adapted to control said third switch and to connect said source of current with said braking means at low speed of said driven shaft and to connect said source of current with said clutching means at high speeds of said driven shaft. f

t. in combination, a. driving man, a driven shaft, a coupling device between said driving shaft and said driven shaft adapted to allow slipping of one of said shafts with respect to the other shaft, a stationary member, cooperating electromagnetic braking means carried by said driven shaft and said stationary member adapted to maintain said driven shaft in a xed position, a source of electric current, connecting .means between said source of currentV and said electromagnetic braking means, a switch inserted in said connecting means, and means responsive to the speed of said driven shaft and adapted tov con-- trol said switch and to close said switch when the speed of said driven shaft is below a determined value and to open said switch when the speed of said driven shaft exceeds said determined value. i

9. in combination, a driving shaft, a driven shaft, a coupling device betweenv said driving shaft and said driven shaft adapted to allow slipping of one of said shafts with respect to the other shaft, a stationary member, cooperating electromagnetic braking means carried by. said driven shaft and said stationary member adapted to maintain said driven shaft in a xed position, a source of electric current, a two-way switch having three terminals, Vone of which being connected with said source of current, two connecting means connected on one hand with said electromagnetic braking means and on the other hand respectively with each of the two other'terminals of said two-way switch, in one of said connecting means a hand operated switch, in the other connecting means an automatic switch, and means responsive to the speed of said driven shaft and adapted to control said automatic switch and to close said switch when the speed of said driven shaft is below a determined value and to open said-switch when the speed of said driven 

